We propose to create a highly informative DNA microarray specifically for gastrointestinal (GI) research with an emphasis on genes associated with inflammatory bowel disease (IBD). RNAs will be harvested from pertinent GI tissues and cell types and screened for genes of high differential expression ("signature biomarker genes") utilizing currently available human DNA microarrays. Gene expression of GI tissues will be profiled against available sequence-validated human cDNAs (ca. 40,000). The 4400 most differentially expressed genes will be selected for inclusion on the array, providing an eight-to-ten fold enrichment of important genes over housekeeping genes. From the selected set of genes we will choose a very informative subset of 384 genes to be triplicated on the array. This triplicate subset will provide statistical validation for what we believe will be some of the most important genes in GI research. Our patent-pending method will drive the selection criteria with a bias toward those genes deemed of particular interest to gastroenterology researchers. The GI array will provide researchers with a cost-effective tool to study gene expression in GI tissues. PROPOSED COMMERCIAL APPLICATIONS: The success of the human genome project has sparked growing interest into the genetics of the GI tract. Our GI array will fill a niche in this market, providing a highly informative and cost effective DNA array for researchers eager to pursue this new technology to develop new clinical diagnostics and in vitro assays for drug therapies. This timely product will complement our best selling dermatology array DermArray(TM).